Observed differences between asbestos and wood communities might be 

 influenced by species preferences, or woodborer activity. For example, 

 spirobid and serpulid worms have exhibited a preference for setting on 

 asbestos cement over wood panels. In contrast, the abundance of a 

 species may be altered between panel types due to the severity of the 

 woodborer activity, since it occurs only on wood panels. Battelle 

 (1977) found that severe infestations of Limnoria spp. reduced the 

 abundance of shipworms and it would seem reasonable that it would effect 

 the distribution of other species as well. As Limnoria spp. populations 

 increase the surface of the wood begins to crumble and attached species 

 are sloughed off. Such effects occurred at Giants Neck, where the 

 lowest asbestos/wood affinities coincided with periods of peak woodborer 

 abundance (February and November) . 



Placement of panels on rack . The location of a panel on a rack 

 can effect the distribution or abundance of an organism (Fig. 5). In 

 May 1980, the location of panels was changed from all replicates being 

 at the same level to three on the top of the rack and three on the 

 bottom (Fig. 1). The objective was to minimize any sampling bias that 

 might create an artificial seasonal effect by having panels from over- 

 lapping exposure periods vertically displaced. Woodborer attacks often 

 become more severe as a substrate approaches the bottom sediments, as 

 observed in 1980 and 1981 (NUSCo 1982). Even though there is only 0.6 m 

 from the bottom of a lower panel to the top of an upper one, the variance 

 for a single species can be considerably increased over the six replicates 

 (Fig. 6). However, fouling species as a group have had only a slight 

 tendancy toward this vertical displacement. For example, the most 

 extreme case of this vertical bias for fouling species occurred in 



15 



